Okay, you wasted hours of work and expensive emulsion trying to burn off a screen and still end up with a crappy screen that doesn’t wash off or is a slimy mess that washes off completely. So how long do I expose my screens? This is the question most new people ask themselves when getting started in screen printing. The answer is a company, that depends.
It depends on the brand and type of emulsion, the number of layers of emulsion on the screen, the time of day, the lunar cycle, and many other factors. The best way to find out the best exposure time is to use a test strip or exposure tool. The exposure tools are printed on a clear plastic and have different gradients from light to dark.
These strips can cost more than $30 dollars, but there is a cheaper way. Take a piece of art that you have printed on acetate and cover a part with construction paper. Expose the screen for one minute. Then, move the construction paper to expose the next part of the art image, and re-expose it for another minute.
Do this 5 times and you’ll end up with a screen with 5 different exposure times, from one minute to five minutes. Wash the screen and the area that washes best is your exposure time. Every time you have problems with exposure, do this test and recalculate your times. You’ll definitely want to do this when you change emulsion/make type or go to another mesh count screen etc.
So start using the test strips today and get great screens that make screen printing easy and fun.
